MRI Adrenal (In/Out of Phase) — Dictation, Appropriateness, and Dose for Residents

1. The Indeterminate Adrenal Nodule — Now What?

You’re reading through the outpatient list. A CT Abdomen and Pelvis for nonspecific pain shows a 1.8 cm, 25 Hounsfield Unit nodule in the left adrenal gland. It’s an incidentaloma. The ordering provider wants to know what it is, and your attending wants a definitive characterization. Is it a benign lipid-rich adenoma, a lipid-poor adenoma, or something more sinister? This is the classic scenario where an MRI of the adrenals with chemical shift imaging becomes your go-to problem-solver. It’s a non-contrast study that can often give you the answer in minutes, without the radiation or complex washout calculations of a dedicated adrenal CT protocol.

When I was a fellow, getting the in-phase and opposed-phase regions of interest (ROIs) just right felt like a high-stakes game. But mastering this study makes you look sharp and provides a clear, confident answer for the clinical team. We’ve built tools and guides like this one over at the residents and fellows resource hub to help you get there faster.

2. What an MRI Adrenal with Chemical Shift Imaging Covers and What Attendings Look For

This study is designed to characterize an adrenal mass, typically one that was found incidentally on another imaging study and was indeterminate. The core of the exam is chemical shift imaging, which leverages the different resonant frequencies of water and fat protons to differentiate lipid-rich adenomas from other adrenal lesions. Your attending is looking for a confident, concise report that answers the primary clinical question.

Here’s what your report needs to nail down:

• Lesion Characterization: Is there a focal adrenal lesion? Measure it in three dimensions.
• Chemical Shift Analysis: Note the signal on T2-weighted images. Critically, describe the signal intensity on in-phase versus opposed-phase sequences. Does it lose signal on the opposed-phase images? If so, it’s likely a lipid-rich adenoma.
• Quantitative Analysis (if applicable): Calculate the Signal Intensity Index (SII) or adrenal-to-spleen ratio to confirm a lipid-rich adenoma.
• Post-Contrast Dynamics (if performed): For lipid-poor lesions, describe the enhancement and washout pattern. Adenomas typically wash out quickly, while metastases and pheochromocytomas retain contrast.
• Ancillary Findings: Comment on the contralateral adrenal gland, the kidneys, and other visualized upper abdominal organs.

3. Radiology Report Template for MRI Adrenal (Chemical Shift Imaging)

This template provides a solid foundation. You can adapt it for your institution’s macros. The key is to be systematic, hitting all the critical points your attending and the referring clinician need to see.

Technique

Multiplanar, multisequence magnetic resonance imaging of the adrenal glands was performed without and with intravenous contrast. Sequences included T2-weighted imaging, in-phase and opposed-phase T1-weighted gradient echo imaging, and dynamic post-contrast T1-weighted imaging in arterial, portal venous, and delayed phases.

Contrast: [Volume] mL of [Contrast Name] was administered intravenously.

Findings

Right Adrenal Gland: Normal in size and configuration. No focal mass or nodularity.

Left Adrenal Gland: There is a [size in cm] mass in the [body/medial limb/lateral limb] of the left adrenal gland. On T2-weighted imaging, the lesion is [isointense/mildly hyperintense/markedly hyperintense] to spleen. On chemical shift imaging, the lesion demonstrates [significant/no significant] signal drop on opposed-phase sequences compared to in-phase sequences. The signal intensity index calculates to [XX]%. The adrenal-to-spleen ratio demonstrates [signal drop/no signal drop].

(If contrast is given) Following contrast administration, the lesion demonstrates [avid/mild/no] arterial enhancement and [rapid/slow] washout on delayed phases.

Kidneys: The kidneys are normal in size and appearance. No hydronephrosis, masses, or perinephric fluid collections.

Other: The visualized spleen, pancreas, liver, and major vessels are unremarkable.

Impression

[Size] cm left adrenal mass, most consistent with a lipid-rich adenoma given the significant signal drop on opposed-phase chemical shift imaging.

— OR —

[Size] cm left adrenal mass, indeterminate. The lesion does not demonstrate signal drop on chemical shift imaging to suggest a lipid-rich adenoma. Post-contrast imaging shows [describe enhancement/washout], which is nonspecific but could represent a lipid-poor adenoma. Recommend clinical and biochemical correlation.

— OR —

[Size] cm left adrenal mass with marked T2 hyperintensity (“lightbulb sign”) and avid enhancement with slow washout, suspicious for a pheochromocytoma. Biochemical correlation is recommended.

Key Principles for Your Impression:

• Chemical Shift: A Signal Intensity Index (SII) >16.5% is diagnostic for a lipid-rich adenoma. SII = (SI_in − SI_out) / SI_in × 100.
• Pheochromocytoma: Look for the “lightbulb sign” (markedly T2 hyperintense) and avid, persistent enhancement.
• Myelolipoma: Contains macroscopic fat, which will drop signal on frequency-selective fat-saturation sequences (not on chemical shift).
• Adrenocortical Carcinoma: Typically large (>4-6 cm), heterogeneous, necrotic, and may show signs of local invasion. These are surgical lesions.

4. Free Radiology Template Sources

Building a personal library of templates is a rite of passage. But you don’t have to start from scratch. Beyond your own institution’s files, two great free repositories exist that are worth bookmarking. They are maintained by radiologists for radiologists, and they cover a huge range of modalities and subspecialties.

• RadReport.org: Curated by the Radiological Society of North America (RSNA), this is one of the most comprehensive libraries of peer-reviewed templates available. (https://radreport.org/)
• Radiology Templates (AU): An excellent, user-friendly site maintained by Australian radiologists with a clean interface and practical templates. (https://www.radiologytemplates.com.au/home-page/)

5. The Next-Level Move: From Free-Form Dictation to a Perfect Report

Templates are a great starting point, but the real magic happens when you can dictate your positive findings naturally and have the report structure itself around them. This is where AI-powered tools can streamline your workflow without getting in your way. Instead of clicking through a rigid template, you can simply dictate the findings as you see them—”2.5 cm left adrenal mass with signal drop on opposed phase, consistent with adenoma”—and the system generates the fully structured report.

Tools like GigHz Precision AI are designed for this. It takes your free-form dictation of positive findings and organizes it into a clean report using pre-loaded templates from the American College of Radiology (ACR) and Society of Interventional Radiology (SIR). It’s designed to help you produce high-quality, attending-ready reports more efficiently, especially on busy calls.

6. When Should You Order an MRI Adrenal with Chemical Shift Imaging? ACR Appropriateness Criteria

The decision to order an adrenal MRI is guided by specific clinical scenarios. The American College of Radiology (ACR) provides evidence-based guidelines to help choose the right test for the right patient. For an adrenal mass found by chance on another scan, the key topic is “Incidentally Discovered Adrenal Mass.”

According to the ACR, an MRI of the adrenal glands is Usually Appropriate for characterizing an adrenal mass that is indeterminate on a prior CT scan. This is especially true if the lesion is too small for accurate washout analysis on CT or if avoiding additional radiation is a priority (e.g., in younger patients or those with multiple prior scans). The primary alternative, and often the first-line study, is a dedicated CT adrenal washout protocol. For patients with a known primary malignancy where an adrenal metastasis is suspected, an FDG PET-CT may also be appropriate.

7. How Much Radiation Does an Adrenal MRI Deliver?

An MRI of the adrenal glands delivers an effective radiation dose of 0 mSv. This is one of the key advantages of MRI over CT for characterizing adrenal lesions, particularly in younger patients or those requiring serial follow-up imaging.

The absence of ionizing radiation makes it a preferred modality when clinically appropriate. To put this in context, a dedicated adrenal protocol CT involves a significant radiation dose, whereas an MRI has none.

8. MRI Adrenal with Chemical Shift Imaging Protocol — Phases, Contrast, and Key Parameters

A successful adrenal MRI hinges on a well-designed protocol. The core components are T2-weighted imaging to look for the classic “lightbulb bright” pheochromocytoma and the chemical shift (in-phase and opposed-phase) sequences to detect intracellular lipid in adenomas. Dynamic contrast-enhanced sequences are added to evaluate lipid-poor lesions.

Common protocol pitfalls: The most common pitfall is misinterpreting the DWI sequence. While pheochromocytomas and malignancies can show restricted diffusion, this finding is not specific and should be interpreted in the context of the other sequences, particularly T2 signal and enhancement characteristics.

9. The 3-Months-Free Offer for Radiology Residents and Fellows

3+ months free for radiology residents and fellows

If you want to look like a rockstar on your reports, we want to help. We’re offering extended free access to GigHz Precision AI for all trainees. You can dictate your positive findings in free form, and the AI will generate a perfectly structured report using ACR and SIR templates, with the appropriate clinical decision support firing automatically. All we ask in return is your feedback so we can keep improving the product for trainees like you.

The signup is simple. No credit card, no long forms. To get set up, just provide these three items:

1. Your PGY year (e.g., PGY-2, PGY-4)
2. Your training type (radiology residency or specific fellowship — IR, body, MSK, neuro, peds, breast, nucs)
3. Your training program / hospital name
4. (Optional) Your institutional email

Ready to give it a try? You can apply for the residents free-access program here.

10. Frequently Asked Questions

Is GigHz Precision AI HIPAA-compliant?

Yes. The platform is designed for de-identified workflows by default. It does not require Protected Health Information (PHI) to function, and all data is handled within a secure, HIPAA-compliant environment.

Do I need my hospital’s IT department to set this up?

No. GigHz Precision AI is a browser-based tool. There is no software to install. It works on any modern web browser, including the one on your call-room computer or personal iPad.

How does this work with PowerScribe or other dictation systems?

It works alongside your current system. Most residents dictate their findings into the tool, let the AI structure the report, and then copy-paste the final, clean text into their official PACS/RIS dictation window. This streamlines the formatting and ensures all key elements are included.

Can I customize the templates?

Yes. While the system comes pre-loaded with ACR and SIR standard templates, you can create, modify, and save your own templates to match your personal style or your institution’s specific requirements.

What happens after I finish my residency or fellowship?

The extended free access is specifically for trainees. After you graduate, you can transition to a standard plan. We offer discounts for recent graduates to help you get started in your practice.